Human bodies are built to move and generally require constant activity to remain supple and healthy. Unfortunately, modern life involves a good deal of sitting; indeed most professions require many hours of simply sitting, which is an unnatural demand on the human bodies—so unnatural that children instinctively rebel against it.
Sitting, and especially sitting still, aligns human bodies oddly, and denies joints the constant small adjustments that help to circulate the joint fluid which helps nourish the delicate cartilage lining of the joints. Additionally, sitting still denies core muscles the exercise involved in aligning and realigning our spines, exercise vital to keeping our core musculature strong and responsive. Further, extended and repetitive sitting has been linked to other health maladies, such as heart attacks.
The biomechanics of the spine allow the body to accommodate numerous primary ranges of motion; namely, spinal movements such as flexion, right and left extension, right and left rotation, lateral bending, as well as long-axis distraction and compression or load/unload cycles. In conventional chairs or seats, motion and/or static position by the user that results in one or more of these spinal movements causes the user's spine and associated soft tissues to absorb the entire motion and the associated stresses. Static spinal positioning or inadequate seat mobility causes a build-up of spinal irritation, soft tissue pressure, muscle spasm, or loss of tone. Further, there can be circulatory disturbance in the spinal soft tissues resulting in significant stress on the user's spine. Without the ability to compensate for and/or produce these essential movements, the user can frequently experience backaches and eventual spinal pathology after prolonged static sitting.